From nature, surfaces of plants and animals are known which, when immersed in water, are wetted to a small extent by the water by virtue of the fact that air is retained in the structure of the surface, such that the immersed parts of the plant or of the animal are not wetted by the water. Said surfaces can be found inter alia in floating aquatic ferns (for example Salvinia molesta) or in water bugs (for example Notonecta glauca). With the aid of the air retained on the surface with layer thicknesses of approximately 1 μm to approximately 1 mm, floating aquatic ferns, for example, can increase their buoyancy, and water bugs can use the air supply carried along underwater for breathing.
However, air escapes as a result of detachment of gas bubbles and as a result of dissolution of the air in the surrounding liquid from the air layer retained on the surface of the plant or of the animal into the surrounding water, such that the air layer is depleted over time. Since the immersion time of a water bug and of a vital floating aquatic fern leaf is however shorter than the time required for consuming the air layer, the dissolution of gases from the air layer into the surrounding water is not a problem.
For technical applications, however, a problem is that of permanently separating the surface of an immersed body from the surrounding liquid by means of an air layer.
Said problem is solved by means of the subjects of the independent claims. The dependent claims relate to preferred embodiments.